removeRange method Null safety
inherited
Removes a range of elements from the list.
Removes the elements with positions greater than or equal to start
and less than end
, from the list.
This reduces the list's length by end - start
.
The provided range, given by start
and end
, must be valid.
A range from start
to end
is valid if 0 ≤ start
≤ end
≤ length.
An empty range (with end == start
) is valid.
The list must be growable.
final numbers = <int>[1, 2, 3, 4, 5];
numbers.removeRange(1, 4);
print(numbers); // [1, 5]
Implementation
@override
void removeRange(int start, int end) {
var length = this.length;
RangeError.checkValidRange(start, end, length);
// Special-case removing an initial or final range because we can do it very
// efficiently by adjusting `_head` or `_tail`.
if (start == 0) {
_head = (_head + end) & (_table.length - 1);
return;
}
var elementsAfter = length - end;
if (elementsAfter == 0) {
_tail = (_head + start) & (_table.length - 1);
return;
}
// Choose whether to copy from the beginning of the end of the queue based
// on which will require fewer copied elements.
var removedElements = end - start;
if (start < elementsAfter) {
setRange(removedElements, end, this);
_head = (_head + removedElements) & (_table.length - 1);
} else {
setRange(start, length - removedElements, this, end);
_tail = (_tail - removedElements) & (_table.length - 1);
}
}